In the metallurgical industry, metallurgical vessels are used which are heated by means of direct current (DC) electricity. In this method, the cathode generally extends into the vessel and the anode is arranged on the bottom of the vessel. The electrical connection device for linking the vessel to a power source, in particular in ladle handling stands and in tundish heating systems, is subject to frequent actuation.
In such a device, the anode can be formed as an individual electrode, for instance as a metallic bar electrode. The lining of the vessel may also be formed of an electrically conductive material so that the vessel or a part thereof forms the anode, and the wall of the vessel is thus used for conducting electrical current.
When the metallurgical vessel is replaced, or when an anode is changed in the event that it has become worn out, the current feed must be detached at a terminal.
European Patent Application No. EP-OS 0,133,931, discloses a threaded connection for the anode connection below the vessel. The disclosed structure has the disadvantage, however, that servicing personnel must manually detach the bottom connection by hand.
European Patent Application No. EP-OS 0,275,384, discloses a connection system having spring-actuated support pins as the contact device. These pins act by pressing the current feed line against the electrode, which are retracted upon the loosening of the electrical contacts in the event of service. The current supply cables are in this case fastened to displaceable straps, which are pivotally mounted.
In the contact device of EP-OS 0,275,384, the tensile or pulling forces resulting from the weight of the current feed line itself, act on the bottom electrode, causing a stress. Furthermore, there is no system or method provided to allow the mechanized introduction of the current feed cable.
Federal Republic of Germany Patent No. DE 0,178,981, discloses a connecting terminal for an electrode of a metallurgical vessel, in which a suspension flange, which holds the electrode, is connected by telescopic arms to the outer wall of the vessel. Elastic elements arranged in the telescopic arms serve to compensate for thermal changes in the length of the electrode. In this device, the electrode is acted on by various pressure forces. The current feed is attached by a threaded flange to the protruding part of the electrode, and can be detached only manually.
European Patent Application No. EP OS 0,344,092, discloses a metallurgical vessel having an opposing electrode, having on its outer shell an element which serves for the transmission of the electrical energy and has a surface which rests on the surface of an opposing element. This opposing element can be positioned by mechanical means.
The system of EP OS 0,344,092 has the disadvantage that, when supported, both elements are acted on by compressive forces, either along the vertical or horizontal axes, depending on the arrangement. By the disclosed use of mechanical means for positioning and adjusting, fixation of the electrode in the desired operating position is possible only within narrow limits.